Handle portion of a toothbrush



FIG. 1 is a perspective front view of a handle portion of a toothbrush showing our new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a bottom view thereof; and,

FIG. 5 is a top view thereof.

The broken line showing of the toothbrush head and of various regions, including the unshaded areas therein, are for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a handle portion of a toothbrush, as shown and described. 